Flexible and overload releasable drive mechanism between drawbar connected vehicles



Jan. 20, 1953 c. M. YERGENS 2,625,000 Y FLEXIBLE AND ovEREoAU REEEASAELE DRIVE MEcEANrsM BETWEEN DRAWBAR CONNECTED VEHICLES Filed June l0, 195C Chasis? M Yernlens.

@Mor/wavy Patented Jan. 20, r1953 UNITED STATES PATENT OFFICE FLEXIBLEv AND' OVERLOAD RELEAS'ABLE DRIVE. MECHANISM BETWEEN DRAW- BAR CONNECTED VEHICLES Chester M.'I,Yergens, Milwaukee, -Wis.

Application June 10, 1950, Serial No. 167,423

2 Claims. 1

This invention pertains generallyto adrive mechanism, and more particularly to `a flexible dri-ving Iconnection between a tractor power takeoff shaft and the drive shaft of an implement.`

Conventional flexible drive connections nov/ in usegconsist of rigid or'splined telescopingshafts connected to the tractor power take-off shaft: and implement drive shaft by universal joints. When exposed 4the universal joints and telescoping shafts Vpresent a serious hazard, due to the fact that unless the .operator uses extremefcaution in stepping vdovvn from the tractor, the protruding universal joints and exposedrevolving -shaftsfrequently become entangled in his garments, resulting in seriousy bodily injury.

To overcome the foregoing, fixed hood guards have been -devised to cover the drive mechanism, 4but inasmuch as these are usually opened at the bottom the crop often becomes Ventangled in the drive mechanism, making it necessary to untangle the same, which requires a tedious operation and loss of time in removing and replacing the guard. Consequently, operators often are carelessly inclined to leave the guard olf.

Therefore, the presentinvention has prim-arily for its pur-pose Ato overcome the foregoing objections by the provision of a flexible drive connection between the tractor and implement, in which no revolvingparts are exposed, thuseliminating danger to the operator and entanglement of the crop.

Incidental to the foregoing, a more specific object of the invention is to provide a drive connection utilizingr a flexible shaft completely housed within a stationary flexible tubular casing, and elimination of universal joints.

A still further object is to provide the present drive connection with a clutch to release the same upon predetermined torque strain, thus preventing damage to both the drive an-d implement, -should the latter become clogged.

In addition to the foregoing, other objects will appear as the description proceeds, and while the accompanying drawing illustrates one complete physical f-orm olf the invention constructed in accordance with the best mode so far devised, it is to be understood that changes in the precise embodiment of the invention are contemplated Within the scope of the appended claims.

In the drawing:

Figure l is an elevational View of a drive mechanism incorporating principles of the present invention, the same being shown applied to a conventional tractor power take-off and implement drive shaft, both of which are illustrated in light lines and lform no partl of the present invention; and

Figure'2 is an .enlarged longitudinal plansec tionalview `ofl the drive mechanism tak-en on the line 2-.2 'of Figure 1.

Referring now more particularly Yto the .accompanying drawing, T indicates the rear vend of ia conventional tractor provided with a power take-off shaft I, journaled in a bearing 2 Vsecured to the lower face of the tractor l differential housing .3. `A'dravv bar 4 attached to the bearing 2=is connected to a tongue l'S'extending from animplement frame F.

The present drive mechanism D is attached at one end to the tractor T, and at the other end to Aa bearing BQcarried-bythe.implement frame F,

which provides a journalffor the implement drive shaft I5.

jAs best :shown in Figure 2, the-'end of the power take-off shaft journaledfat itsrearvend in the bearing 2, is lprovided with a spline extension I for reception of a sleeve 8, fast against longitudinal movementon the spline by a pin 9. Secured Within the reduced rear end of the sleeve lIl is a flexible drive `shaft -I0, which may beof either the 'spiral Wound type illustrated, or a conventionallink-shaft.

Secured upon lthe rear end of the `flexible'drive shaft I0 is a squared shank II, splined within a sleevey I2 for longitudinal movement. The rear end of the sleeve I2 is provided with a toothed clutch head I3, normally engaging a complementary head I4 secured on the implement drive shaft I5, which projects through the head I3 to hold the same in longitudinal alignment with the head I4.

Surrounding the flexible drive shaft I0 is a flexible tubular casing I6, which may be of conventional metallic, reinforced fabric or rubber construction. The Aforward end of the casing IS i-s secured within a collar I1, which in turn is fastened lWithin the end of a housing I8 attached to the rear face of the bearing 2 and surrounding the sleeve 8 attached to the 4spline end I of the tractor power take-off shaft I.

The rear end of the ilexible casing I-6 is secured Within an annular flange I9 formed on one end of a tubular shell 20, slidably mounted on a cylindrical housing 2I attached to the bearing 5 carried by the implement frame F. The shell 20 is held against rotation on the housing 2l by bolts 22 extending through longitudinal slots 23 formed in the shell.

A coil spring 24 interposed between the clutch head I3 and a spanner nut 25, threaded 'into the interior of the annular housing ZI, serves to hold the clutch head I3 into engagement with the complementary clutch head I4, and obviously, in the event of excessive torque strain on the drive, the clutch head I 3 is free to shift out of operative engagement with the head I4, against predetermined pressure of the spring, 24, which may be regulated by adjustment of the spanner nut 25.

In operation, it will be apparent that flexibility of the shaft I and casing IB permits free relative turning action between the tractor and implement, and consequent variation in the distance between the tractor bearing 2 and implement bearing 6 will be compensated for by the spline connection lbetween the shank I I and the splined sleeve I2. At the same time the slidable connection between the shell 20 and the housing 2I allows corresponding longitudinal movement of the flexible casing I6,

From the foregoing explanation, considered in connection with the accompanied drawing, it will be readily seen that an effective flexible drive connection for use between a tractor `and implement has been devised, in which no rotatable parts are exposed to endanger the operator, or entangle the crop.

While'not essential to the fundamental principle of the present invention, the torque release clutch provided is considered highly advantageous, particularly in the present application, for the purpose of eliminating possible damage to the flexible drive shaft in the event of excessive torque strain should the implement become fouled.

I claim:

1. vA flexible releasable `drive mechanism for use between a, tractor power take-off shaft and the drive shaft of a draw-bar connected implement comprising, a flexible drive shaft, operative connections between said exible drive shaft and the tractor power take-off shaft and the implement drive shaft, one of said connections including a spline to allow relative axial movement between the flexible drive shaft and adjacent connected shaft, a spring clutch interposed between one end of said flexible drive shaft and adjacent connected shaft to operatively release said exible shaf-t upon predetermined torsional strain, a flexible non-rotatable tubular casing surrounding said flexible drive shaft, a rigid connection between one end of said tubular casing and either said tractor or implement, and a slidable connection between the opposite end of said tubular casing and said tractor or implement to allow free relative longitudinal movement between said non-rotatable casing and tractor or implement to compensate for relative axial movement between said flexible drive shaft and adjacent connected shaft.

2. A flexible releasable drive mechanism for use between a tractor power take-off shaft and the drive shaft of a draw-bar connected implement comprising, a flexible drive shaft, operative connections between said flexible drive shaft and the tractor power take-off shaft and the implement drive shaft, one of said end connections including a spline to allow relative axial movement between said flexible shaft and adjacent connected shaft, a spring clutch interposed between one end of said flexible shaft and adjacent connected shaft to operatively release said flexible shaft upon predetermined torsional strain, stationary housings encasing the endsof said tractor power take-off shaft and said implement drive shaft, a flexible non-rotatable tubular casing surrounding said exible shaft, a, rigid connection between one end of said tubular casing and one of said housings, and a slidable connection between the opposite end of said tubular casing and the other of said housings to allow free relative longitudinal movement between said non-rotatable casing and said housing to compensate for relative axial movement between said flexible drive shaft and adjacent connected shaft.

CHESTER M. YERGENS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,138,926 Bernett May 11, 1915 1,769,510 Herman July 1, 1930 1,771,703 Berill July 29, 1930 2,030,511 Gruber Feb. 11, 1936 2,275,004 Behl Mar. 3, 1942 2,390,908 Young Dec. 11, 1945 2,517,721 Schleper Aug. 8, 1950 

